1. Field of the Invention
The present invention relates to a sensor equipped wheel support bearing assembly having a load sensor built therein for detecting a load acting on a bearing unit of a vehicle wheel.
2. Description of Related Art
As a technique to detect a load acting on any one of vehicle wheels of an automotive vehicle, a sensor equipped wheel support bearing assembly has been suggested in, for example, the patent document 1 listed below, in which detection is made of strains occurring in a flange portion outer diametric surface of an outer ring (an outer member), forming a stationary ring, of the wheel support bearing assembly. In addition, such a wheel support bearing assembly as shown in FIG. 43 has also been suggested in, for example, the patent document 2 listed below, in which a strain gauge 51 is pasted to an outer ring 50 of the wheel support bearing assembly for the purpose of detecting strains.
Yet, the inventors of the present invention has ever suggested a sensor equipped wheel support bearing assembly of a structure, in which a sensor unit, comprised of a strain generating member and a strain sensor fitted to this strain generating member, is fitted to a stationary ring of the bearing assembly, which strain generating member has at least two contact fixing segments relative to the stationary ring and also has at least one cutout portion defined between the neighboring contact fixing segments with the strain sensor arranged in this cutout portion. In this respect, see, for example, the patent document 3 listed below.
According to the sensor equipped wheel support bearing assembly disclosed in the patent document 3 listed below, since when a load acts on a rotatable ring then rotating incident to travel of the automotive vehicle, the stationary ring is deformed through rolling elements, such deformation leads to a strain induced in the sensor unit. The strain sensor provided in the sensor unit detects the strain induced in the sensor unit. If a relation between the strain and the load is determined by means of a series of experiments and/or simulations beforehand, the load, for example, which has been imposed on the vehicle wheel may be detected from an output of the strain sensor.